Let's make up an example. Let's say you earn $75,000/year and the tax rate is 10%. So you owe $7,500 in taxes. That is your tax liability. It doesn't matter if you have your employer deducting $144 from your weekly paycheck or $0 from your weekly paycheck.

https://apps.irs.gov/app/understandingTaxes/student/hows.jsp